• International Journal of Highway Engineering
• /
• v.18 no.2
• /
• pp.91-101
• /
• 2016

PURPOSES : The aim of this study was to compare the performance of the QUEENSOD method and the gravity model in estimating Origin-Destination (O/D) tables for a large-sized microscopic traffic simulation network. METHODS : In this study, an expressway network was simulated using the microscopic traffic simulation model, VISSIM. The gravity model and QUEENSOD method were used to estimate the O/D pairs between internal and between external zones. RESULTS: After obtaining estimations of the O/D table by using both the gravity model and the QUEENSOD method, the value of the root mean square error (RMSE) for O/D pairs between internal zones were compared. For the gravity model and the QUEENSOD method, the RMSE obtained were 386.0 and 241.2, respectively. The O/D tables estimated using both methods were then entered into the VISSIM networks and calibrated with measured travel time. The resulting estimated travel times were then compared. For the gravity model and the QUEENSOD method, the estimated travel times showed 1.16% and 0.45% deviation from the surveyed travel time, respectively. CONCLUSIONS : In building a large-sized microscopic traffic simulation network, an O/D matrix is essential in order to produce reliable analysis results. When link counts from diverse ITS facilities are available, the QUEENSOD method outperforms the gravity model.

• Advances in concrete construction
• /
• v.1 no.3
• /
• pp.239-252
• /
• 2013

Mortar microstructure is considered as a three-phase composite material, which is cement paste, fine aggregate and interfacial transition zone. Interfacial transition zone is the weakest link between the cement paste and fine aggregate, so it has a significant role to determine the properties of cementitious composites. In this study, specimens (w/c = 0.35, 0.45, 0.55) with various volume fractions of fine aggregate ($V_f$ = 0, 0.1, 0.2, 0.3 and 0.4) were cast and tested. To predict the equivalent migration coefficient ($M_e$) and migration coefficient of interfacial transition zone ($M_{itz}$), double-inclusion method and Mori-Tanaka theory were used to estimate. There are two stages to estimate and calculate the thickness of interfacial transition zone (h) and migration coefficient of interfacial transition zone ($M_{itz}$). The first stage, the data of experimental chloride ion migration coefficient ($M_s$) was used to calculate the equivalent migration coefficient of fine aggregate with interfacial transition zone ($M_e$) by Mori-Tanaka theory. The second stage, the thickness of interfacial transition zone (h) and migration coefficient of interfacial transition zone ($M_{itz}$) was calculated by Hori and Nemat-Nasser's double inclusion model. Between the theoretical and experimental data a comparison was conducted to investigate the behavior of interfacial transition zone in mortar and the effect of interfacial transition zone on the chloride migration coefficient, the results indicated that the numerical simulations is derived to the $M_{itz}/M_m$ ratio is 2.11~8.28. Additionally, thickness of interfacial transition zone is predicted from $10{\mu}m$, 60 to $80{\mu}m$, 70 to $100{\mu}m$ and 90 to $130{\mu}m$ for SM30, M35, M45 and M55, respectively.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.20 no.5
• /
• pp.75-82
• /
• 2021

The number of traffic accidents is about 230,000, and due to non-recurring congestion and high driving speed, the number of deaths per traffic accident on freeways is more than twice compared to other roads. Currently, traffic information is provided based on nodes and links using the centerline of the road, but it does not provide detailed speed information. Recently, installing sensors for vehicles to monitor obstacles and measure location is becoming common not only for autonomous vehicles but also for ordinary vehicles as well. The analysis using large-capacity location-based data from such sensors enables real time service according to processing speed. This study presents an mapping method for individual vehicle data analysis based on space. The processing speed of large-capacity data was increased by using method which applied a quaternary notation basis partition method that splits into two directions of longitude and latitude respectively. As the space partition was processed, the average speed was similar, but the speed standard deviation gradually decreased, and decrease range became smaller after 9th partition.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.3
• /
• pp.632-637
• /
• 2019

Recent researches on autonomous driving of vehicles are becoming very active, and it is a trend to assist safe driving and improve driver's convenience. Autonomous vehicles are required to combine artificial intelligence, image recognition capability, and Internet communication between objects. Because mobile telecommunication networks have limitations in their processing, they can be easily implemented and scale using an easily expandable Wi-Fi network. We propose a wireless design method to construct such a vehicle control network. We propose the arrangement of AP and the software configuration method to minimize loss of data transmission / reception of mobile terminal. Through the design of the proposed network system, the communication performance of the moving vehicle can be dramatically increased. We also verify the packet structure of GPS, video, voice, and data communication that can be used for the vehicle through experiments on the movement of various terminal devices. This wireless design technology can be extended to various general purpose wireless networks such as 2.4GHz, 5GHz and 10GHz Wi-Fi. It is also possible to link wireless intelligent road network with autonomous driving.

• International Journal of Internet, Broadcasting and Communication
• /
• v.13 no.4
• /
• pp.112-120
• /
• 2021

Recently, the number of consumers using digital online distribution platforms is increasing. This caused the rapid growth of the e-commerce market and increased delivery volume in urban areas. The logistics system, designed ar006Fund the city center to handle the delivery volume, operates a delivery system from the outskirts of the city to the urban area using cargo trucks. This maintains an ecosystem of high-cost and inefficient structures that increase social costs such as road traffic congestion and environmental problems. To solve this problem, research is being conducted worldwide to establish a high-efficiency urban joint logistics system using urban railway facilities and underground space infrastructure existing in existing cities. The joint logistics system begins with linking unmanned delivery automation services that link terminal delivery such as cargo classification and stacking, infrastructure construction that performs cargo transfer function by separating from passengers such as using cargo platform. To this end, it is necessary to apply the device to the vertical and horizontal transportation machine supporting the vertical transfer in the flat space of the joint logistics terminal, which is the base technology for transporting cargo using the transfer robot to the destination designated as a freight-only urban railway vehicle. Therefore, this paper aims to derive holistic viewpoints needs for design requirements for vertical and vertical transportation machines and freight transportation standard containers, which are underground railway logistics transport devices to be constructed by urban logistics ecosystem changes.

• Journal of the Korean Society of Industry Convergence
• /
• v.23 no.6_2
• /
• pp.1015-1024
• /
• 2020

By nature, smart construction technology is a convergence technology, therefore aptly constructing and running an information system is needed in order to effectively develop and maintain it. Thus, in this study, an information system prototype was developed for the creation and linking of high precision digital maps at road construction sites for the effective performance of the development of the Information Collecting and Analyzing Techniques in the Construction Site (ICAT). For this, (1) defined input/output (I/O) data of each technical detail of ICAT, (2) analyzed the data flow, (3 ) proposed an information system prototype for high precision digital maps development and connection. Based on the information system prototype constructed in this study, it was inferred that each technique and its information for the Smart Construction Technique Development Business was in a consistent flow. Developed information system prototype would enable effective cooperation between subjects directly involved in the technique development, by defining I/O data in advance. Moreover, it would be of value to practitioners for refining the output data from each technique, thereby linking databases and forming Entity Relationship Diagram.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.17 no.2
• /
• pp.369-390
• /
• 2023

Technologies for disaster management are highly sought areas for research and commercial deployment. Landslides, Flood, cyclones, earthquakes, forest fires and road/train accidents are some causes of disasters. Capturing video and accessing data in real time from the disaster site can help first responders make split second decisions which may save human lives and valuable resource destructions. In this context the communication technologies performing the task should have high bandwidth and low latency which only 5G can deliver. But unfortunately in India, deployment of the 5G mobile communication systems is yet to give a shape and again in remote areas unavailability of 4G signals is still severe. In this situation the authors have proposed, simulated and experimented a 4G-5G communication scheme where from the disaster site the signals will be transmitted by a 5G terminal to a nearby 4G-5G gateway installed in a mobile vehicle. The received 5G signal will be further relayed by the 4G-5G gateway to the fixed 4G base station for onward transmission towards the disaster management station for decision making, deployment and relief monitoring. The 4G-5G gateway acts as a relay and converter of 5G signal to 4G signal and vice versa. This relayed system can be further mounted on a vehicle mounted relay (VMR) as proposed by 3GPP in Release 18. The scheme is also in the same line of context with Verizon's, "Tactical Humanitarian Operations Response" (THOR) vehicle concept. The performance of the link is studied in different channel conditions, the throughput achieved is superb. The authors have implemented the above mentioned system towards smart campus networking and monitoring landslides activities which are common in their regions.

• International conference on construction engineering and project management
• /
• 2011.02a
• /
• pp.299-303
• /
• 2011

Congestion is a growing concern of many global cities and the demands on Infrastructure services within a locale coupled by the rising expectations from the growing population places stress on these cities. This entails the ability to build a sustainable community that requires an understanding and recognition of Population growth, changing demographics and the ever changing urban development on both a macro and micro level. Infrastructure is an integral part of Australian economy, particularly the 'Infrastructure Assets Management' which highlights the importance towards the development of sustainable communities for Melbourne's future. Melbourne 2030 is a comprehensive representation of government's response to a wide-ranging population growth within Melbourne metropolitan and surrounding areas. Urban plan and specific Infrastructure Assets Planning needs not only to provide sufficient Infrastructure to a community, but it must also be efficient and innovative so that it produces an optimised management system. A system that incorporates engineering techniques that will be sustainable for decades to come by maintaining an acceptable level of services to its intended community in an effective manner, which also strengthens service delivery. The fundamental challenges for optimization of Infrastructure with the Melbourne urban plan is, the ability to manage and sustain maintenance of Infrastructure to provide the acceptable level of service required by the community in a most effective manner which also strengthens service delivery to contribute towards Melbourne 2030. This paper particularly investigates some of the fundamental issues within the Melbourne urban plan such as Infrastructure Asset Management, AusLink and the Australian Road Management Act 2004, which the Governments at all levels must deal with to provide an economically viable solution to the changing Infrastructure so it may suits the needs and services the strategies of a metropolis.

• Journal of Korean Society of Transportation
• /
• v.30 no.2
• /
• pp.101-116
• /
• 2012

Accident prediction models have been utilized to predict accident possibilities in existing or projected freeways and to evaluate programs or policies for improving safety. In this study, a traffic accident prediction model for freeways was developed for the above purposes. When selecting variables for the model, the highest priority was on the ease of both collecting data and applying them into the model. The dependent variable was set as the number of total accidents and the number of accidents including casualties in the unit of IC(or JCT). As a result, two models were developed; the overall accident model and the casualty-related accident model. The error structure adjusted to each model was the negative binomial distribution and the Poisson distribution, respectively. Among the two models, a more appropriate model was selected by statistical estimation. Major nine national freeways were selected and five-year dada of 2003~2007 were utilized. Explanatory variables should take on either a predictable value such as traffic volumes or a fixed value with respect to geometric conditions. As a result of the Maximum Likelihood estimation, significant variables of the overall accident model were found to be the link length between ICs(or JCTs), the daily volumes(AADT), and the ratio of bus volume to the number of curved segments between ICs(or JCTs). For the casualty-related accident model, the link length between ICs(or JCTs), the daily volumes(AADT), and the ratio of bus volumes had a significant impact on the accident. The likelihood ratio test was conducted to verify the spatial and temporal transferability for estimated parameters of each model. It was found that the overall accident model could be transferred only to the road with four or more than six lanes. On the other hand, the casualty-related accident model was transferrable to every road and every time period. In conclusion, the model developed in this study was able to be extended to various applications to establish future plans and evaluate policies.

• Korean Journal of Heritage: History & Science
• /
• v.48 no.3
• /
• pp.186-203
• /
• 2015

This article attempts to examine both the outcome and future task of the art history research on Central Eurasia, better known under the name of "Silk Road". The term Central Eurasia encompasses Xinjiang Uygur, Tibet, Mongolia, former Soviet Republics, the northwest region of India, Iran and Turkey. The article analyzes the 30-year history of the region's art history research and further presents a desirable direction that the study should move towards. Though short in its research period, the ROK's art history study on Central Eurasia has shown eye-catching achievement in several areas such as the northwest region of India and the Xinjiang Uygur, Dunhwang of China. Two factors allowed for this accomplishment. First was the actual improvement of the work environment, where the scholars were finally able to travel to Central Eurasia and explore the historic sites for themselves since 1990. More important was the 'arena of study' for the next-generation scholars made possible by institutions like The Korean Association for Central Asian Studies and the Center for Central Eurasian Studies. Slowly but consistently, the two academic societies induced scholars' attention towards the field and fostered new experts. Circumstances changed, marking 2012 as the starting point. International academic forums held by the government branches surged in number. The intention behind it was to link the ROK with the Silk Road and ultimately to obtain the "Eurasia initiative". As of now, the public has shown heightened interest in the issue. The academia is subsequently riding on this second "wave of interest" following the first wave in the 1980s. However, increased popularity comes with some negative consequences, and this art history research on Central Eurasia is no exception. There are criticisms regarding the objectivity of recent academic forums. Some argue that the aim of the forums are sternly set most of the times, prohibiting the presenters to voice their own perspectives. Still, this heated attention will definitely play its role as a stepping stone for further development. The academia should commit to fostering rising researchers who will systemically and professionally study the field. This is imperative in order for the Korean culture to successfully communicate with the world and take itself to a new level. Without completing this task, the ROK's art history research on Central Eurasia is likely to remain idle.